THE SINGLE-PHASE MOTOR. 



Ratio of Transformation. 105. We shall see that it is not advisable 

 to cover the whole circumference of the field with windings. In gen- 

 eral, it will be advantageous to wind but two-thirds of it. The ratio of 

 transformation in this case is not equal to the quotient of the number 

 of conductors in the field divided by the number of conductors in the 

 armature. With sufficient accuracy we may consider the ratio of trans- 



FIG. 2Q. 



formation to be equal to the number of active conductors in the field 

 divided by only five-sixths of the total number of active conductors 

 in the armature. 



EXPERIMENTAL CORROBORATION. 



106. The data given in the following table, and graphically repre- 

 sented in the polar diagram, Fig. 29, belong to a lo-hp, single-phasi 

 current motor for no volts, 50 ~, and 1500 r. p. m. The number of 

 conductors in the field was 120; the number of conductors in the 



59 



